Junction temperature

About: Junction temperature is a research topic. Over the lifetime, 5058 publications have been published within this topic receiving 58643 citations.

Teaching thermal design of power electronic systems with web-based interactive educational software

Abstract: For designing reliable power electronic systems it is essential to understand basic thermal issues like the stationary and transient relation of the power semiconductor losses the junction temperature and the application of thermal equivalent circuits. Also, thermal properties are of special importance in connection with further increasing the compactness of power converter systems. The aim of this paper is to give an introduction into the basic theory of heat energy conduction and thermal design which should serve as an addition to the Java applets compiled in a the iPES-Thermal, a module of the interactive educational software iPES which is freely available at www.ipes.ethz.ch and employed at the ETH Zurich for supporting an introductory course on power electronics.

Investigation on Thermal Characterization of Eutectic Flip-Chip UV-LEDs With Different Bonding Voidage

Abstract: Flip-chip ultraviolet light-emitting diode (FC UV-LED) fabricated by direct AuSn eutectic package is of high interest in Research and Development due to its excellent thermal performance and good reliability. However, the voids in eutectic bonding layer due to the lack of AuSn filled have a big influence on the thermal management and optical performance of FC UV-LEDs, and it is believed that the eutectic voids can affect the thermal-conduction resistance (the following unified called thermal resistance) and the junction temperature of FC UV-LEDs. In this paper, modeling and thermal simulation using finite element analysis is developed by considering the geometrical model of eutectic FC UV-LEDs with 3%, 10%, 20%, and 30% bonding voidage. Meanwhile, to validate the simulation, the thermal parameters of FC UV-LEDs are determined and measured using thermal transient tester, and it is found that UV-LED with 3% voidage shows lowest thermal resistance and junction temperature compared with the other samples in both simulation and experiment. Moreover, the optical performance of UV-LEDs is evaluated via the photoelectric analysis system, and the results confirm that the lowest thermal resistance leads to the lowest junction temperature but the highest light output power.

Active gate driving method for reliability improvement of IGBTs via junction temperature swing reduction

Abstract: This paper introduces an advanced gate driver used as thermal swing control method for the reduction of AC load current-related ΔT j in Insulated-Gate Bipolar Transistors (IGBTs). A switchable gate resistor network is applied to the advanced gate driver, so that the switching power losses can be changed according to the amplitude of AC current. Accordingly, a closed-loop thermal control method including the functions of root-mean-square calculation and phase analysis is proposed. Hence ΔT j can be reduced by means of changing losses-related gate resistors on the basis of output fundamental frequency and amplitude of AC load current. As a result, longer device useful life duration can be achieved. Furthermore, the maximum junction temperature under high-temperature operation can be reduced by means of the proposed method. Simulations and experiments are provided to validate the effectiveness of the proposed active gate driver.

Integrated circuit speed controller

Abstract: A speed control circuit made by using CMOS processes is capable of handling high voltage and high current loads. The output of the speed control circuit is provided by a power field effect transistor. Current sensing means are provided to generate a fault signal in case an over current condition occurs. The junction temperature of the power field effect transistor is also monitored to provide an over temperature condition if the temperature of the junction of the power field effect transistor exceeds a predetermined value. A ramping generator is used to set a latch which controls the operation of the power field effect transistor. A speed control signal is compared against the ramping signal provided by the ramp generator and resets the latch in order to provide speed control.

An Integrated Liquid Metal Thermal Switch for Active Thermal Management of Electronics

Abstract: Heat dissipation is a key obstacle to achieving reliable, high-power-density electronic systems. Thermal devices capable of actively managing heat transfer are desired to enable heat dissipation optimization and enhanced reliability through device isothermalization. Here, we develop a millimeter-scale liquid metal droplet thermal switch capable of controlling heat transfer spatially and temporally. We demonstrate the thermal switch by integrating it with gallium nitride (GaN) devices mounted on a printed circuit board (PCB) and measure heat transfer and temperature of each device for a variety of switch positions and heat dissipation levels. When integrated with a single GaN device (2.6 mm $\times4.6$ mm face area) dissipating 1.8 W, the thermal switch shows the ability to actively control heat transfer by conducting 1.3 W in the ON mode with the GaN device at 51 °C ± 1 °C, and 0.5 W in the OFF mode with the GaN device at 95 °C ± 1 °C. To elucidate the heat transfer physics, we developed a 1-D system thermal resistance model in conjunction with an independent 3-D finite-element method (FEM) simulation, showing excellent agreement with our experimental data. Finally, we demonstrated that when the switch is integrated with two GaN devices, the switch can balance the device heat transfer rate and enhance junction temperature uniformity and system reliability by lowering the device-to-device temperature difference from > 10 °C (no switch) to 0 °C.